DESCRIPTION: (verbatim from application) The traditional assumption when fabricating a transtibial amputee (TTA) socket is that the residual limb is not homogeneous in its ability to tolerate load. As a result, a plaster model of its shape is altered by the prosthetist to produce a socket (i.e., rectified socket). We have diverged from the traditional assumption and the associated rectified socket fabrication process, and except for a distal end pad, have shaped the socket precisely to the contours of the patient's limb (i.e., unrectified socket). Testimonials and objective outcomes indicated either no differences as a function of socket type, or favored the unrectified socket. The purpose of this study is to compare rectified and unrectified sockets in TTAs. Specific Aim 1: compare patient satisfaction of transtibial amputees wearing both rectified and unrectified sockets. Sixty adults with a transtibial amputation (TTA group) will fill out the Prosthesis Evaluation Questionnaire (PEQ) after wearing a rectified socket (rectified condition) and after wearing an unrectified socket (unrectified condition). A patient will wear each socket for a minimum of 4 weeks before completing the questionnaire. The PEQ quantifies patient satisfaction by evaluating 9 validated scales. At the end of participation, each patient will freely choose the socket they wish to have included in the final prosthesis. Our null hypothesis is that no difference will exist between scales and between final prosthesis selection for the rectified and unrectified sockets. Specific Aim 2: compare measures of function of transtibial amputees wearing both rectified and unrectified sockets. Functional measures will also be collected from the TTA group under the two different socket conditions. Function will be measured by energy expenditure, kinematics, and ground reaction forces during gait. Our null hypotheses are that: 1) no difference will exist between measures for the rectified and unrectified conditions, and 2) no difference will exist between measures for the prosthetic and nonprosthetic limb under both socket condition.